New Mail server setup

Question

Greetings,
I need some pro's cons, Ideas taunts and general whaddia thinks.
Setting up a new mail server. dpG5 xserve w/ 10,000 rpm drives
my thoughts are to take the user information off the machine to a second G5 xserve running as an ODM.
I thought about splitting IMAP/pop services to another box. keeping my primary SMTP Spam/AV away from cyrus, relaying inbound messages to the IMAP server.
so I would have
ODM.mydomain
SMTP1.mydomain
IMAP1.mydomain
-- Does anyone see any performance or configuration hick ups here?
now comes the ugly question.
How do I set up each smtp server. the imap server is still going to have to run smtp to deliver and recieve delivery of messages. but I need them to answer for mydomain, not host1.mydomain. I'm a little foggy on what comes first
--j

Answer 1

There are multiple ways of achieving this.
The simplest is for the servers to deliver via smtp to each other.
So (very very simplified):
Since you said you use OD, I assume all servers will refer to your OD master for user account details.
Server 1 (Filter)
Postfix & amavisd & ClamAV & spamassassin
main.cf and master.cf should be configured like you are used to now except that you only want to be able to send to the content filter and nowhere else.
In amavisd.conf uncomment and change IP (to IP of SMTP/IMAP server) of this line:
$forward_method = 'smtp:127.0.0.1:10025';
No relay settings needed, because you want mail to go the filter first and not to another SMTP server.
Server 2 (Mail Stores)
Postfix & Cyrus
main.cf and master.cf should be configured like you are used to now except that you do not want any kind of filtering anymore. Also set to accept only from Server 1 (since it should not accept incoming mail from the outside world directly)
Server 3 (Outgoing SMTP)
Postfix
main.cf and master.cf should be configured like you are used to now except that you do not need to accept incoming mail. Also no filtering needed (unless you want to scan outgoing mail)
Mail clients:
Point incoming to Server 2 and outgoing to Server 3
That's pretty much it. I know it's not a walkthrough , but then again this kind of setup is better fully understood rather than copied step-by-step.
Let me know if you need anything else.
Alex
P.S.
-Optionally you could use Server 3 as a secondary MX for backup reasons.
-For most Postfix settings see : http://www.postfix.org/postconf.5.html
-All of this can be further improved with firewall rules